1. Field of the Invention
The present invention relates to a mechanism for positioning a glass fiber relative to a semiconductor laser.
2. Description of the Prior Art
Both glass fiber lines and semiconductor elements that generate optical emissions are used for communications-oriented transmissions. In particular, the semiconductor elements commonly used are laser diodes. The known laser diodes generate a relatively highly focused radiation and have a comparatively small radiation emitting face on the semiconductor body from which the laser emission is generated. The area of laser emission, commonly referred to as a diameter, has the dimensions of a few .mu.m.
Since the glass fiber used for optical transmissions has an effective propagating cross-section of a comparable dimension, considerable expense is required to provide an adequately precise adjustment between the glass fiber line and the laser diode. A good coupling of the laser emission into the glass fiber can only be guaranteed for adjustment tolerances of a few .mu.m.
In U.S. Pat. No. 4,411,057, which corresponds to European patent application No. 0,006,042, is disclosed an adjustment device which has an adjustment member of a material which is deformable with an extrusion die. A V-shaped groove is impressed for the glass-fiber and a planar depression is impressed for the laser diode. The side walls of the planar depression have such a great distance from one another that the laser diode can be attached in this depression laterally displaceable by a considerable amount.
In U.S. Pat. No. 4,466,696 is disclosed an adjustment device having a V-shaped groove for accepting a glass fiber which is etched into the substrate member of a laser diode. Since the V-shaped groove is situated in the body of the laser diode, once the position is established, it is permanently fixed. The etching of the V-shaped groove and the complicated technological manufacture of the laser diode with epitaxial steps and the like, however, these steps are executed on a single member, which has a substantially complicating effect on the overall manufacturing process due to the different measures which must be executed in chronological succession.
An adjustment having two abutting members is disclosed in Applied Phys. Lett., Vol. 45 (1984), pages 729-731, and in particular, in FIG. 1. A first of the two abutting members carries the laser diode. The second member abutting the first member forms a transversely proceeding rectangular depression together with the first member which receives a capillary tube.
In the publication IBM Technical Disclosure Bulletin, Vol. 23 (1980), pages 3104 through 3106, and in particular, at FIGS. 1 and 2, a semiconductor member having a V-shaped groove, into which a glass fiber is inserted, is shown. The laser diode forms a part of this semiconductor member. A channel that has slanting edges is formed in the surface of the member and is a component part of the actual diode function. At an upper side of the member lying between the slanting edges is a metal diode which is on the semiconductor material of the laser diode and recessed in the channel. There is no further member in the channel which can be used to adjust the channel in any way.
The German Patent No. OS 33 30 992 discloses a cooling member provided with a V-shaped groove. A laser diode soldered to the cooling member can be used to adjust the laser diode on the cooling member. The principal function of the groove is to keep the laser diode which is soldered to the cooling member free of disturbing mechanical stresses which would otherwise be exerted on the laser diode by the cooling member. The groove in the cooling member cannot be used to adjust a coupled glass fiber.